[help beta L4D] how do I re enable beta bullet casings sound?

[saibot_20194]

there's a folder called: weapons/fx/tink/shotgun_shell1.wav and in the script folder is the game_sounds_physics.txt connected to that sound folder, now my question is how do I re enable it? by scripting or commands? it seems that valve just disable it for unknown reasons...

in the beta was enabled just like counter strike source and half life 2 and you can hear the shells casings bouncing in the trailer, but for the final cut of left 4 dead they disabled the sound. I need professional help with this, thanks in advance.

regards saibot_20194.